Phosphine or hydrogen phosphide (PH3) is a low
molecular weight, low boiling point compound that diffuses
rapidly and penetrates deeply into materials, such as large bulks
of grain or tightly packed materials. The gas is produced from
formulations of metallic phosphides (usually aluminium or
magnesium phosphide) that contain additional materials for
regulating release of the gas.

AIP + 3H2O à PH3^
+ Al(OH)3

Mg3P2 + 6H2O à 2PH3^ + 3Mg(OH)2

Aluminium phosphide is formulated 8S tablets, pellets or small
sachets of powder with additional materials such as ammonium
carbamate, ammonium bicarbonate, urea and paraffin to regulate
release of fumigant and suppress flammability. The magnesium
phosphide is similarly manufactured in tablets or pellets. It is
also prepared in flat plates; here the formulation is embedded in
a plastic matrix that regulates access of moisture and hence
controls release of the gas. After the phosphine has evolved from
a formulation, the residue that remains consists mainly of
aluminium or magnesium hydroxide. Small amounts of undecomposed
aluminium phosphide may also remain in the greywrlite dust from
tablets, pellets or sachets.

A strong odour, resembling carbide or garlic, is normally
associated with the evolution of phosphine from various
formulations. It can be detected by smell even at very low
concentrations. This odour seems to be due to the presence of
other compounds produced along with phosphine and they may be
preferentially absorbed during fumigation treatments. Under some
conditions the odour may disappear, even when insecticidally
effective concentrations are still present in the free space of a
fumigation system (Bond and Dumas, 1967; Dumas and Bond, 1974).
While any odour associated with the evolution of phosphine may
indicate the presence of phosphine, it should not be relied on
for warning purposes.

TOXICITY

Phosphine is very toxic to all forms of animal life, hence
exposure of human beings even to small amounts should be avoided.
Poisoning can result from ingestion or inhalation; however, the
gas is not absorbed through the skin. A concentration of 2.8 mg/l
(ca 2 000 ppm in air) is lethal to humans in a very short time
(Flury and Zernik, 1931). The threshold limit value is usually
set at 0.3 ppm for a 40-hour work week. Symptoms of poisoning for
humans are described below under "First Aid".

Phosphine ranks as one of the most toxic fumigants of stored
product insects (see Chapter 14, Table 16). It is a slow acting
poison that is effective at very low concentrations if the
exposure time is long enough. Usually, exposure times of four or
more days are required to control insects, depending on
temperature. The toxicity of phosphine to insects declines as the
temperature falls to 5°C, so that longer exposure times are
required for it to exert its effect. It is not recommended for
use below 5°C. The exposure time cannot be shortened by
increasing the dosage; in fact, high concentrations can have a
narcotic effect on insects thereby reducing mortality (Winks,
1974a).

Phosphine has an inhibitory effect on insect respiration and
is unique in that it is only toxic to insects in the presence of
oxygen - in the absence of oxygen it is not absorbed and is not
toxic to insects (Bond et al 1967, 1969). However, the action of
phosphine is potentiated by carbon dioxide and the exposure time
can be reduced when both gases are present (Kashi and Bond,
1975).

Some stages of insects are considerably more tolerant to
phosphine than others (Bell, 1976; Hole et al, 1976; Nakokita and
Winks, 1981). The eggs and pupae are usually hardest to kill
while larvae and adults succumb more easily. Reynolds et al
(1967) found that this tolerance was at least partially overcome
by the development that occurred in the insects during the
relatively long exposure periods. For example, a 10-day exposure
of various stages of Sitophilus Granaries was found to be long
enough to permit the different stages to reach a susceptible
point of development at some time during the fumigation. These
results suggest that all pre-adult stages, some of which are
quite tolerant to the fumigant, may reach a susceptible stage of
development during a 10-day fumigation, so that an exposure
period of this length will lead to complete mortality. Howe
(1974) discussed problems relating to the laboratory
investigation of phosphine toxicity to storedproduct insects.

Observations to date on the effectiveness of phosphine on
mites in bulks of grain indicate that the fumigant may be
successful in bringing about immediate reduction in mite
populations and thus improving the condition of the grain (Van
den Bruel and Bollaerts, 1956). However, populations of some
species have been seen to build up again in the grain after an
interval of time. This is partially due to the fact that natural
predators such as the mite, Chevletus eruditus (Schr.), are
eliminated and partially because some stages of destructive
species of mites are resistant to the fumigant (Heseltine and
Thompson, 1957; Sinha et al, 1967). Tests on dried prunes have
shown that satisfactory control of mites on this commodity can be
obtained with phosphine (Cangardel and Fleurat-Lessard, 1976).

Insect Resistance

The effectiveness of phosphine can be reduced considerably by
development of resistance in insects. Winks (1974b) showed that
Tribolium castaneum could develop 10-fold resistance to phosphine
in six generations. Resistance may occur in immature stages as
well as in adult insects. Bell et al (1977) found a good
correlation between resistance in the adult stage of Rhyzopertha
dominica and resistance in the egg stage. Champ and Dyte (1976)
found evidence of resistance to phosphine in insects from several
parts of the world, particularly where inadequate techniques of
fumigation were employed, and they indicated that emergence of
resistance to fumigants under practical conditions was a matter
of great concern. There is recent evidence (Borah and Chalal,
1979; Tyler et al, 1983) of the development of resistance to
phosphine in field populations of Khapra beetle and other insects
infesting stored grain. Hole (1981) discussed the variation in
tolerance of seven species of stored-product Coleoptera to
phosphine in strains from twenty-nine countries. Further
information on the nature and occurrence of resistance is given
in Chapter 2.

EFFECT ON PLANT LIFE

Seeds

There is considerable evidence from studies so far conducted
that phosphine in insecticidal treatments does not, under normal
conditions, affect the germination of seeds. Strong and Lindgren
(1960b) tested cereal, sorghum and small legume seeds with one or
two (repeat) fumigations at comparatively high concentrations.
Berstlief and Alexandrescu (1964) confirmed these findings for
wheat sod maize under Rumanian conditions and Pinto de Matos
(1961) for the germination of groundouts. When a third fumigation
was done with phosphine, Fam et al (1974) found no ill effect on
the germination of some varieties of tomatoes, sweet melons,
cucumbers, peas and beans, but one variety of broad beans was
slightly affected. However, the growth and yield of plants grown
from seeds subjected to repeated fumigations with phosphine may
be significantly reduced. Joubert and Du Toit (1969) reported a
reduction in total yield of maize grown from seed fumigated twice
sod three times with phosphine.

Living Plants

There is little information on the tolerance of growing plants
to the vapours of phosphine. Monro and Upitis (1967) found that
15 varieties of glasshouse plants were tolerant to concentrations
which were completely toxic to the postembryonic life stages of
the mealybug Plannococcus citri (Risso), but the eggs were not
killed. The nematode Meloidopyne hapla may be controlled in
potted rose plants with phosphine applied to the soil, without
apparent injury to the plants (Faber, 1966).

EFFECT ON PLANT PRODUCTS

Phosphine has been used for many years to control insects in a
wide range of plant products throughout the world. To date there
has been no report of appreciable adverse effects from
recommended treatments.

Mayr and Hild (1966) concluded that normal fumigation with
phosphine has no effect on vitamins, particularly vitamins A and
B2 (riboflavin), in a group of important foods which
are a regular dietary source of these vitamins. Fumigation of
wheat with phosphine under normal conditions has no adverse
effect on the baking quality of flour made from it (Neitzert,
1953; Lindgren et al, 1958; Mayr, 1974; Matthews et al, 1970a,b).
Phosphine can also be used to control insects (Nelson, 1970;
Vincent and Lindgren, 1971) and mites (Cangardel and
Fleurat-Lessard, 1976) in dried fruit.

Tests on fresh fruit and vegetables show that insects such as
fruit flies can be controlled using gas generated from a
magnesium phosphide preparation without injury to the produce.
Seo et al (1979) found no injury on papaya, tomato, bell pepper,
eggplant or banana fumigated with dosages that eliminated eggs
and larvae of the fruit flies Dacus dorsal) Hendl. and Ceratitis
capitata Wied. Ten varieties of avocado, although not injured by
the treatment, did ripen more quickly than unfumigated avocados.
Grapefruit and tomatoes have also been fumigated without injury
at concentrations sufficient to kill fruit flies (von Windeguth
et al, 1977; Spalding et al, 1978).

The use of phosphine for bulk grain fumigation is described in
Chapter 10. Recommended treatments for a number of plant
products, including packaged foods, will be found in Schedule P.

RESIDUES IN FOODSTUFFS

The residues resulting from the use of phosphine fumigants may
be of three types: reaction products of the formulation,
unchanged phosphine absorbed in commodity or products formed by
chemical combination of phosphine with components of the
commodity.

Formulations of aluminium or magnesium phosphide leave mainly
an inert residue of the metallic hydroxide. In formulations of
aluminium phosphide, a small amount of unreacted material may
also remain, and hence some precautions should be taken to avoid
hazards from the unspent formulation. When processed foods are
Fumigated, or when space fumigations are carried out, residue
from the formulation should be collected and properly disposed
of.

Residue from magnesium phosphide in the plate preparations
remains in the plastic matrix in which it is embedded as
magnesium hydroxide. The reaction with water vapour is
substantially complete, so that no abreacted material remains,
and elimination of the residue simply involves collection and
disposal of plastic trays at approved sites.

Unchanged phosphine does not remain in fumigated commodities
in appreciable amounts. Tolerance levels of 0.1 mg/kg for raw
grains and 0.01 mg/kg for processed foods have been established
by many agencies and numerous investigations have shown that the
gas desorbs rapidly during aeration to levels well below the
tolerances (see review by Dietrich et al, 1967). It is
interesting to note, however, that minute but detectable traces
of phosphine can remain in fumigated commodities for very long
periods of time. Dumas (1980) detected phosphine desorbing from
fumigated wheat 220 days after the treatment.

Some reaction products may form by combination of phosphine
with components of a commodity. Several investigations have shown
that small quantities of innocuous phosphites and phosphates from
phosphine remain in fumigated materials (Robinson and Bond, 1970;
Disney and Fowler, 1972; Tkachok, 1972; Underwood, 1972).

Recommendation for Tolerances

Taking into account the fact that phosphine aerates rapidly
from foodstuffs, and that a residue of 0.1 mg/kg in a raw cereal
would yield a much lower residue in bread or other food ready for
consumption, the FAD/WHO joint meeting (1967a) considered that
there was no necessity to establish a figure for acceptable daily
intake. For cereals in international trade a tolerance of 0.1
mg/kg expressed as PH3 is recommended.

METHODS OF ANALYSIS

Determination of Vapours

For the determination of concentrations of phosphine used in
fumigation, glass detector tubes (Figure 18) are available from a
number of manufacturers in various ranges from 15 to 3 000 ppm.
These tubes, described more fully in Chapter 3, are reasonably
reliable, easy to use and are of sufficient accuracy for
monitoring approximate concentrations achieved at various stages
in a fumigation. For protection of personnel from low levels of
phosphine around the threshold limit value (TLV), similar tubes
with ranges down to 0.025 ppm can be obtained. A mixed indicator
paper strip that will give rapid, sensitive and reliable
detection of phosphine around the TLV has been developed by Kashi
and Muthu (1975).

Infra-red analysers have been used on an experimental basis
for analysis of phosphine and found to have good stability,
reproducibility and sensitivity (Webley et al, 1981). The
concentration of phosphine is determined by measurement of
absorption bands at either 4.2 µm or at 9.0 µm unless carbon
dioxide is present; carbon dioxide interferes with analysis of
phosphine at 4.2 µm and may need to be absorbed from the sample
or the analysis may be done at 9.0 µm. In normal use, sampling
can be done by pumping fumigant - air mixture through the
analyses but there is also a closed loop injection system for
calibration of the instrument or for experimental work. Here
small samples can be injected through a septum by a gas syringe.
With the infra-red analyses, concentrations up to 2.7 mg/l have
been measured under field conditions and, with proper
manipulation, levels down to 0.0004 mg/l (0.25 ppm) can be
detected.

Gas chromatography has been developed and used extensively for
analysis of phosphine in experimental work (Dumas, 1964, 1969;
Chakrabarti and Wainman, 1972; Bond et al, 1977). Small, portable
gas chromatography suitable for analysing phosphine in commercial
treatments are now available on the market. One such instrument
that is simple, easy to use and virtually unaffected by air and
high moisture levels can measure phosphine below 0.02 ppm (Barker
and Leveson, 1950).

Determination of Residues

The problem of determination of residual phosphine in
fumigated foodstuffs has been reviewed by Dietrich et al (1967).
A sensitive method, developed by Bruce et al (1962) and modified
by Sullivan and Murphy (1966) has been widely used for analysis
of phosphine residues in many commodities. Kroeller (1968)
described a sensitive method with a simplified procedure for
plotting the calibration curve using high purity potassium
dibydrogen phosphate. These methods are sensitive to less than
0.005 mg/kg.

For analysis of desorbing residual phosphine by gas
chromatography the method of Dumas (1978) can be employed.

FORMULATIONS

Both aluminium and magnesium phosphide are manufactured in
several different formulations for a variety of applications.
Aluminium or magnesium phosphide powder is compressed into hard
round or flat tablets about 3 9 in weight or pellets of 0.6 9,
which yield approximately 1 and 0.29 of phosphine, respectively.
Aluminium phosphide powder is also prepared in permeable paper
bags or sachets. Additional materials such as paraffin and
ammonium carbamate or ammonium bicarbonate are included in the
formulations to regulate moisture uptake and to dilute the
phosphine as it is generated. The products are supplied in sealed
metal tubes, cans or flasks, which are packed in cases. As long
as the containers remain sealed the storage life of the product
is virtually unlimited. The pellets and round tablets are
supplied in flasks that can be resealed after opening.

For convenience and safety, pellets or sachets are sometimes
supplied in predetermined quantities for specific applications.
Pellets are prepared in special prepacks of 165 pellets each for
treatments such as railway box car fumigations. Similarly,
sachets are joined together in ropes or in "blankets".
In these prepared packages the pellets or sachets are separated
sufficiently to avoid a build up of excessive heat and
concentrations of the gas in small spaces.

Magnesium phosphide is also marketed in the form of a flat
plate about 280 x 170 x 5 mm and weighing 2069. The active
ingredients of the formulation are embedded an inert polyvinyl
acetate matrix fabricated in the form of a semi-rigid plate
covered on both sides with moisturepermeable paper. Every plate
is individually sealed in a gas-impermeable foil pouch, or 16
plates interconnected to form a 4 480 mm strip, are similarly
sealed in foil and packaged in tins - 32 plates per tin or two
strips of 16 plates each.

Once the plates or strips are removed from the foil pouches,
they start evolving phosphine within one half to one hour. This
formulation is intended to be used for fumigation of bulk goods
and packaged and processed commodities. It can be applied
successfully under almost nil space storage conditions provided
that the structure is tightly sealed. According to the
manufacturer, this formulation can also be used to fumigate
fruits and vegetables at recommended dosages without any adverse
effects, such as phytotoxicity.

The plates and strips provide ease of application and
collection after the treatment; there is no danger of
contaminating goods with spent fumigant as the plastic matrix
retains all such material. Magnesium phosphide formulations
release the phosphine more rapidly than aluminium phosphide
products, with the maximum gas reading usually being achieved
within the first 24 hours.

Magnesium phopshide made in discs weighing 10 9 for control of
burrowing rodents and moles is for outdoor use only.

Handling of Phosphine Formulations

Containers of aluminium or magnesium phosphide formulations
have labels that give important information concerning use,
hazards and precautions. The instructions on the labels should be
carefully adhered to during fumigation. Containers should be
opened in the open air where any released gas can readily diffuse
away. Caution: DO NOT OPEN IN A DUSTLADEN OR EXPLOSIVE
ATMOSPHERE. The formulation should be kept away from liquid
or water, as this causes immediate release of the gas with
possible spontaneous ignition. Also, piling of the formulation or
residual dust may cause a temperature increase so that a flash
may occur. Gloves should be worn by the person handling the
phosphine formulation and smoking or eating should be avoided
until the hands are washed after application. Containers with
screw type caps are made to be gas-tight and may he resealed if
only part of the contents are used. When containers are emptied
they should be triple-rinsed with water to remove any traces of
abreacted product and then disposed of in an approved disposal
site.

APPLICATION

Because phosphine is highly toxic, inhalation of even small
quantities of the dust from the formulation, as well as the
evolved yes, should be avoided. Pellets or tablets may be applied
directly to a grain stream by hand (protected by gloves) or by
means of automatic applicators. The rate that the yes evolves
from the formulation varies, depending on type of formulation,
moisture and temperature. In grain, for example, if the moisture
content and temperature are high, all of the gas from aluminium
phosphide formulations is evolved within three days. Special
probes are used for applying tablets below the surface of bulk
grain. Sachets may be applied directly to the grain stream,
pushed into the grain bulk or inserted into specially designed,
permanently installed pipes in grain bins (Anon, 1980). For some
treatments the sachets are laid out in blankets on the surface of
grain to allow the gas to evolve and diffuse into the grain mass.
Methods of application of phosphine formulations for bulk grain
are described and illustrated in Chapter 10.

For the treatment of bagged grains and other raw commodities
in transport facilities, such as railway wagons, pellets or
tablets may be spread evenly over the load or placed in moisture
permeable envelopes to fit in some convenient location near the
door before closing. When fumigating packaged commodities under
gas-proof sheets the tablets or pellets can be spread out on
trays to lay under the sheet before it is secured. In warehouses,
after the structure is adequately sealed, the tablets or pellets
are spread out on trays or sheets of Kraft paper so that residual
material can be easily collected at the end of the treatment. The
tablets or pellets should never be piled on top of each other or
in a mass.

On completion of the fumigation, all windows and doors should
be opened and the space aerated for at least two hours. A gas
reading should be taken with a suitable analyses before entering
the fumigated area. If it is necessary to enter the fumigated
space to open doors and windows a gas mask with a canister
designed for phosphine must be worn.

Disposal of Spent Reaction Products

After a fumigation, any residual material left from the
reaction process should be disposed of in an approved manner.
This can be accomplished by burying or by slowly adding the dust
to a container of water (with detergent as a wetting agent) and
stirring into the water until a slurry is formed and the residue
sinks. If prepacks have been used the entire strip should be
submerged in the water-detergent mixture and allowed to soak for
36 hours before disposal. For purposes of safety the disposal
procedure should be carried out in the open air, where any
generated phosphine can rapidly disperse.

Spent plates or prepack strips may be held out of doors in
locked wire containers and moved to an approved disposal site at
monthly intervals, or whenever the container is full.

In fumigation treatments of raw agricultural commodities such
as grain or bulk animal feeds, no special disposal procedures are
needed because any of the phosphide formulation that may remain
is further decomposed and removed along with grain dust in the
handling and turning that accompanies further processing of the
grain (liscombe, 1963).

PRECAUTIONS

Reaction with Metals

Phosphine is practically insoluble in water, fats anti oil and
is stable at normal fumigation temperatures so that it has no
appreciable reaction with most fumigated commodities. It may,
however, react with certain metals, particularly copper, copper
compounds, silver and gold to cause corrosion. This reaction is
enhanced by the presence of ammonia, which is given off during
the decomposition of some proprietary formulations. High humidity
and temperature appear to favour the reaction, particularly in
air with a salt content as found near the sea.

As a result of this reaction any copper-containing equipment,
especially electrical apparatus, may be severely damaged. During
fumigation of buildings with phosphine special attention should
be given to electric motors, electric wiring, switches, fire
alarm systems, electronic systems or other pieces of equipment
that contain copper (Bond et al, 1984).

If equipment that is liable to damage cannot be removed from
the area being treated some protection may be afforded by coating
copper materials with a thin layer of paraffin, spraying with a
light lubricating oil or using techniques that will keep the
concentration of phosphine and the humidity low.

Concentrations Toxic to Humans

The threshold limit value-time weighted average (TLV-TWA) for
an eighthour daily exposure in a five-day week is set at 0.3 ppm
(ACGIH, 1981). The maximum concentration to which workers should
be exposed for a period up to 15 minutes is 1 ppm, with the
stipulation that at least 60 minutes should elapse between such
exposures and provided the daily TLV-TWA of 0.3 ppm is not
exceeded.

Should a person become exposed to phosphine as a result of
inattention, negligence, failure to follow proper procedures or
some other reason and, as a result, symptoms consisting of
fatigue, ringing in the ears, nausea, or pressure in the chest
appear, he should go immediately into the open fresh air.
Symptoms of poisoning by a small quantity of phosphine will
normally disappear when a person is removed to the fresh air.
However, despite the seeming insignificance of even mild cases of
poisoning with symptoms as described above, first aid measures
(see below) are absolutely imperative before and until the
arrival of a doctor.

Under no conditions should an affected person resume work
during the next 48 hours, particularly work dealing with
fumigation, as it takes time for the body to eliminate the poison
completely. Complete abstinence from alcholic beverages after any
poisoning is strongly recommended.

Respiratory Protection

For personal protection against the vapours of phosphine at
concentrations above the threshold limit, a respirator, gas
blouse or other similar equipment for supplying uncontaminated
air must be used. Respirators with a special canister for
phosphine vapours will give protection up to 0.5 percent
phosphine by volume in air (Kloos et al, 1966). Above this
concentration, air must be supplied by an air-line or
self-contained breathing equipment. Appropriate detection
equipment for measuring concentrations of phosphine in air should
be used in conjunction with respiratory protective devices to
ensure adequate protection.

General Precautions

Full precautionary instructions are supplied by the
manufacturers of the proprietary materials used for generating
phosphine. Some of the more important precautions are listed
here.

1. Gloves should be worn when tablets or pellets are being
dispensed by hand.

2. Respirators need not be worn when tablets or pellets
are being dispensed under conditions where the operator does
not breathe the vapours of phosphine. Under normal
conditions, there is a delay in evolution of the fumigant
from the formulations described in this manual. Respirators
equipped with a canister designed for protection against
phosphine (see above) or other appropriate respiratory
equipment should always be on hand in case of emergency.

3. Odour of the fumigant cannot be relied upon as an
indication of whether or not the operator is breathing
poisonous concentrations. Detection equipment such as glass
detector tubes or other detectors should be used to monitor
concentrations of the gas and to determine when an area is
free of fumigant after a treatment.

4. Do not smoke or touch food at any time during the
applicaion of this insecticide.

5. Any spaces adjoining silo bins or close to other
structures undergoing treatment with phosphine should be kept
continuously aired by leaving windows open or by providing
artificial ventilation by means of fans or blowers.

6. All persons working, or likely to work, in any place
near the fumigation area must be notified that fumigation is
in progress. Warning notices should be posted to prevent
exposure of employees or the public at large to the gas.

7. When the fumigation is completed and the grain is
turned, or aeration of a structure is undertaken, full
precautions must be undertaken to ensure that no person is
exposed to residual vapours of the fumigant.

FIRST AID

Symptoms of Poisoning

According to the amount of phosphine inhaled, symptoms may
occur immediately or several hours after exposure.

Slight or mild poisoning may give a feeling of fatigue,
ringing in the ears, nausea, pressure in the chest and
uneasiness. All of these symptoms will normally disappear in
fresh air.

Greater quantities will quickly lead to general fatigue,
nausea, gastrointestinal symptoms with vomiting, stomach ache,
diarrhoea, disturbance of equilibrium, strong pains in the chest
and dyspnoea (difficulty in breathing).

Very high concentrations rapidly result in strong dyspnoea,
cyanosis (bluish-purple skin colour), agitation, ataxia
(difficulty in walking or reaching), anoxia (subnormal blood
oxygen content), unconciousness and death. Death can be immediate
or occur several days later due to oedema and collapse of the
lungs, paralysis of the respiratory system or oedema of the
brain. Disturbances of kidney and liver functions (hoematuria,
proteinuria, uraemia, jaundice) and cardiac arrhythmia may occur.

Advice to the Physician

The following measures are suggested by the manufacturer for
use by the physician in accordance with his own judgement.

In its milder forms, symptoms of poisoning may take some time
(up to 24 hours) to make their appearance, and the following
measures are suggested:

1. Complete rest for one or two days, during which the
patient is kept quiet and warm.

2. Should the patient suffer from vomiting or increased
blood sugar, appropriate intravenous solutions should be
administered. Treatment with oxygen breathing equipment is
recommended as is the administration of cardiac and
circulatory stimulants.

In cases of severe poisoning intensive care in a hospital is
recommended:

1. Where pulmonary oedema is observed, steroid therapy
should be considered and close medical supervision is
recommended. Blood transfusions may be necessary.

2. In case of manifest pulmonary oedema, venesection
should be performed under vein pressure control, and
intravenous administration of glycosides (in case of
haemoconcentration, venesection may result in shock). On
progressive oedema of the lungs, perform immediate incubation
with constant removal of oedema fluid and establishment of
oxygen positive pressure respiration, as well as any measures
required for shock treatment. In Case of kidney failure,
extracorporeal haemodialysis is necessary. There is no
specific antidote known for this poison.

3. Suicide may be attempted by taking solid phosphides by
mouth. In such a case, empty the stomach by inducing vomiting
and flush it with a dilute potassium permanganate solution or
a solution of magnesium peroxide until the flushing liquid
ceases to smell of carbide. Thereafter, administer medicinal
charcoal.

4. Scientific research has shown that phosphine poisoning
is not chronic; the action of phosphine is reversible and
symptoms will disappear by themselves.